I have had great success converting books and adding them to my KOBO using Calibre. However, this last time, after sent several epubs to my device then removed it, it did its normal "proccessing new content" thing and when it was finished ALL of my content was missing. I did a reset and I believe all of my books are back but many are missing cover images in the list view. They still seem to have covers when in sleep mode or when powered off when Im reading one. Not a HUGE problem since I still have the books and can read them but a problem that bothers me nonetheless.